948
FXUS66 KMFR 220539
AFDMFR
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE MEDFORD OR
1039 PM PDT MON SEP 21 2026
..UPDATED THE AVIATION AND MARINE SECTIONS
AVIATION...22/06Z TAFS
ALONG THE COAST, IFR IS PRESENT NORTH OF
CAPE BLANCO AND NEAR BROOKINGS. A MARINE PUSH OVERNIGHT INTO TUESDAY
MORNING WILL BRING IFR ALONG THE ALL OF THE SOUTHERN OREGON COAST,
AND A MIX OF MVFR AND IFR CEILINGS INTO THE UMPQUA VALLEY. THERE IS
ALSO A 60% PROBABILITY OF MVFR CEILINGS EXTENDING INTO JOSEPHINE
COUNTY (INCLUDING GRANTS PASS) AND 20% PROBABILITY OF MVFR CEILINGS
REACHING INTO JACKSON COUNTY (INCLUDING MEDFORD). LOW CEILINGS ARE
EXPECTED TO CLEAR TO VFR BETWEEN 18-21Z. FOR OTHER INLAND AREAS,
EXPECT CONTINUED VFR THROUGH THE TAF PERIOD.
MARINE...UPDATED 800 PM PDT MONDAY, SEPTEMBER 21, 2026
GUSTY NORTH WINDS WILL MAINTAIN STEEP SEAS SOUTH OF CAPE BLANCO
THROUGH TUESDAY EVENING, EXCEPT FOR VERY STEEP SEAS SOUTH OF GOLD
BEACH AND WITHIN 30 NM OF SHORE. THIS INCLUDES NEAR SHORE WINDS
SOUTH OF BROOKINGS BECOMING STRONG TUESDAY AFTERNOON AND EVENING.
CONDITIONS IMPROVE SLIGHTLY WEDNESDAY AND MORE NOTICEABLY ON
THURSDAY, BEFORE A THERMAL TROUGH STRENGTHENS AGAIN ON FRIDAY.
PREV DISCUSSION
/ISSUED 404 PM PDT MON SEP 21 2026/
KEY MESSAGES...
* SEASONABLE TEMPERATURES AND DRY CONDITIONS WILL PREVAIL MOST OF
THIS WEEK.
* RAIN CHANCES INCREASE THURS/FRI (20%-60%) WITH ISOLATED
THUNDERSTORM POSSIBLE (10%-20%) ALONG AND WEST OF THE CASCADES.
* THE FRONT WILL BE MOSTLY DRY EAST OF THE CASCADES, BUT WILL
PRODUCE GUSTY SOUTHWEST WINDS.
* COOLER TEMPERATURES AND DRY CONDITIONS ARE THEN EXPECTED THROUGH
THE WEEKEND.
DISCUSSION...A CLOSED UPPER-LEVEL LOW IS PASSING TO THE SOUTH OF
THE FORECAST AREA TODAY, PLACING SOUTHERN OREGON AND FAR NORTHERN
CALIFORNIA UNDER THE DEFORMATION ZONE BETWEEN IT AND THE MAIN BELT
OF WESTERLIES TO OUR NORTH. THIS WILL KEEP CONDITIONS QUIET
ACROSS THE AREA TODAY, WITH PLENTY OF HIGH LEVEL CLOUDS AND SOME
LOCALIZED CUMULUS BUILDUPS, MAINLY OVER HIGHER TERRAIN. THERE IS A
VERY LOW CHANCE ONE OF THE CUMULUS COULD DEEPEN ENOUGH TO FORM A
LIGHT SHOWER, AND AN EVEN SMALLER CHANCE FOR A THUNDERSTORM TO
DEVELOP, HOWEVER, GIVEN THAT HIGH CLOUDS WILL LIKELY LIMIT DAYTIME
HEATING AND DESTABILIZATION, NEITHER OF THESE IS LIKELY TO OCCUR.
AS THE LOW OPENS AND EXITS TO THE EAST, WE WILL EXPERIENCE MOSTLY
ZONAL FLOW OVER THE FORECAST AREA FOR THE NEXT SEVERAL DAYS,
WHICH WILL LEAD TO GENERALLY QUIET WEATHER WITH VERY LITTLE
IMPACTS OR HAZARDS. THE NEXT UPPER-LEVEL TROUGH ARRIVES OFFSHORE
BY EARLY THURSDAY MORNING, THEN IT AND AN ASSOCIATED COLD FRONT
WILL MOVE ONSHORE LATE THURSDAY INTO EARLY FRIDAY THIS WILL
INTRODUCE A CHANCE OF SHOWERS AND A SLIGHT CHANCE OF THUNDERSTORMS
ALONG AND WEST OF THE CASCADES, BUT THE FRONT WILL BE MOSTLY DRY
AND WILL MAINLY PRODUCE GUSTY WINDS TO THE EAST OF THE CASCADES.
THERE IS STILL SOME UNCERTAINTY ABOUT THE EXACT TIMING OF THESE
FEATURES, WHICH COULD MAKE A DIFFERENCE IN THUNDERSTORM CHANCES.
CURRENT MODEL TRENDS SUGGEST INSTABILITY WILL BE VERY MEAGER, SO
WE ARE NOT EXPECTING MUCH IN THE REALM OF THUNDERSTORM CHANCES,
BUT LIGHT RAINFALL SEEMS LIKELY, ESPECIALLY ALONG THE COAST AND
COASTAL MOUNTAINS.
THEREAFTER, TEMPERATURES DROP AS THE TROUGH PUSHES EASTWARD. FOR
EXAMPLE, MEDFORD MAY ONLY REACH THE UPPER 60S FOR A HIGH ON FRIDAY
WITH TEMPERATURES STRUGGLING TO REACH THE LOWER 70S THROUGH THE
WEEKEND. IN OTHER WORDS, EXPECTING A COOL DOWN LATER IN THE WEEK
TO BELOW NORMAL TEMPERATURES IN THE WAKE OF THE UPPER TROUGH
ACROSS THE REGION.
MFR WATCHES/WARNINGS/ADVISORIES
OR...CA...NONE.
PACIFIC COASTAL WATERS...SMALL CRAFT ADVISORY UNTIL 11 PM PDT TUESDAY
FOR PZZ356-376.
HAZARDOUS SEAS WARNING UNTIL 11 PM PDT TUESDAY FOR PZZ356-376.
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